Approximation algorithms and hardness results for labeled connectivity problems

Let G=(V,E) be a connected multigraph, whose edges are associated with labels specified by an integer-valued function ℒ:E→ℕ. In addition, each label ℓ∈ℕ has a non-negative cost c(ℓ). The minimum label spanning tree problem (MinLST) asks to find a spanning tree in G that minimizes the overall cost of the labels used by its edges. Equivalently, we aim at finding a minimum cost subset of labels I⊆ℕ such that the edge set {e∈E:ℒ(e)∈I} forms a connected subgraph spanning all vertices. Similarly, in the minimum label s – t path problem (MinLP) the goal is to identify an s–t path minimizing the combined cost of its labels. The main contributions of this paper are improved approximation algorithms and hardness results for MinLST and MinLP.     

The enemies within: targeting Han Chinese and Hui minorities in Xinjiang

How can we account for the targeted pattern of violence in Xinjiang, in which Uyghur secessionist groups attack some second-order minorities such as the Han Chinese and the Hui, but not the sizeable populations of Kazak, Kyrgyz, and Mongol minorities? Based on a variety of primary and secondary sources, I argue that members of the Han minority, being the national majority in China but a ‘nested minority’ in Xinjiang, are doomed to become a primary target of secessionist attacks as they represent, in and of themselves, the state from which Uyghur nationalists are trying to secede. Han Chinese’s – and to a lesser extent the Hui’s – economic and political dominance over the Uyghurs, along with their lack of historical ties to Xinjiang, also motivates their targeting while reinforcing the bond between other indigenous and comparatively disadvantaged minorities.     

Stock Exchange Markets in Hong Kong: Structure and Main Problems

With reference to a previous analysis of the characteristics and morphology of the stock markets of Mainland China (Shanghai and Shenzhen), the study aims at completing the overview of the main Asian stock exchanges (excluding Japan), by examining the Hong Kong stock exchange. After a review of the main literature, the paper considers the historical-legislative process that has defined the current organizational-functional structure of the market. The analysis also shows the main statistical data of the market (number of listed companies, trading volume, performance of the main indices, etc.). For every considered phenomenon, the study suggests plausible explanations. The paper also provides further considerations about the main issues of the market, through a comparison with the stock exchanges of Mainland China.     

Internal migration and the politics of place: a comparative analysis of China and Indonesia

Spontaneous and organized population movements have long been used as a means of promoting a country's goals of development and national integration. At the local level, on the other hand, these movements have frequently done the opposite, fueling local grievances, sharpening group distinctions, and at times creating ‘sons-of-the-soil’ conflicts. In this paper, I explore this apparent tension between the national political rationale for internal migration and the political impact such migration has had locally, in four minority regions of China and Indonesia. I argue that the specific manner in which migration affects local politics is influenced by a country's political regime. In Indonesia, the impact of migration is observed in electoral politics, where ‘politics of place’ have been allowed to emerge. In China, it is perceived in the curbing of national minorities’ territorial autonomy. The role played by local elites and group competition between indigenous people and migrants are also reviewed.     

Social Enterprise Performance: The Role of Market and Social Entrepreneurship Orientations

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - Market orientation has been presented as an important predictor of business performance, and it is presumed to contribute...     

From Rags to Riches? Immigration and Poverty in Spain

This article for first time explores the relationship between immigration and poverty in Spain. Using recent Spanish household surveys, it is found, first, that both moderate and severe poverty are more acute among immigrants than among nationals and social transfers play no substantial role in reducing monetary deprivation in the case of foreign-born population; in the second place, we perform an econometric analysis that shows that the different poverty risk faced by local and immigrant households is not driven by differences in basic household and demographic characteristics.     

Italian Social Enterprises at the Crossroads: Their Role in the Evolution of the Welfare State

This paper investigates the relationship between the emergence of social enterprises (SEs) and the historical development of the Italian welfare state. Our research offers a comprehensive overview of the internal and external influences that shaped the constitutive relations between the welfare state and SEs. A qualitative methodology based on semi-structured interviews and focus groups has been adopted. This study suggests that two interconnected dynamics—the emergence of new social needs being answered by private organisations and the increased prominence of third sector actors during the privatisation of the welfare state—shaped the co-evolution of the welfare state and SEs in Italy. The study also suggests that the emergence and evolution of Social Enterprises in the years leading up to 2001 was mainly a bottom-up phenomena stemming from the actions of citizens setting up private organisations (often cooperatives) to answer to social problems created by new social needs and the structural reform of the welfare state. After 2001 especially with the new law on SEs in 2016, the evolution of SEs seems to have been increasingly influenced by the surrounding ecosystem of actors and supranational policy discourses rather than SEs themselves.     

Tests for noninferiority trials with binomial endpoints: A guide to modern and quasi‐exact methods for biomedical researchers

Applied statisticians and pharmaceutical researchers are frequently involved in the design and analysis of clinical trials where at least one of the outcomes is binary. Treatments are judged by the probability of a positive binary response. A typical example is the noninferiority trial, where it is tested whether a new experimental treatment is practically not inferior to an active comparator with a prespecified margin δ. Except for the special case of δ = 0, no exact conditional test is available although approximate conditional methods (also called second‐order methods) can be applied. However, in some situations, the approximation can be poor and the logical argument for approximate conditioning is not compelling. The alternative is to consider an unconditional approach. Standard methods like the pooled z‐test are already unconditional although approximate. In this article, we review and illustrate unconditional methods with a heavy emphasis on modern methods that can deliver exact, or near exact, results. For noninferiority trials based on either rate difference or rate ratio, our recommendation is to use the so‐called E‐procedure, based on either the score or likelihood ratio statistic. This test is effectively exact, computationally efficient, and respects monotonicity constraints in practice. We support our assertions with a numerical study, and we illustrate the concepts developed in theory with a clinical example in pulmonary oncology; R code to conduct all these analyses is available from the authors.     

Probability and Possibility‐Based Representations of Uncertainty in Fault Tree Analysis

Expert knowledge is an important source of input to risk analysis. In practice, experts might be reluctant to characterize their knowledge and the related (epistemic) uncertainty using precise probabilities. The theory of possibility allows for imprecision in probability assignments. The associated possibilistic representation of epistemic uncertainty can be combined with, and transformed into, a probabilistic representation; in this article, we show this with reference to a simple fault tree analysis. We apply an integrated (hybrid) probabilistic‐possibilistic computational framework for the joint propagation of the epistemic uncertainty on the values of the (limiting relative frequency) probabilities of the basic events of the fault tree, and we use possibility‐probability (probability‐possibility) transformations for propagating the epistemic uncertainty within purely probabilistic and possibilistic settings. The results of the different approaches (hybrid, probabilistic, and possibilistic) are compared with respect to the representation of uncertainty about the top event (limiting relative frequency) probability. Both the rationale underpinning the approaches and the computational efforts they require are critically examined. We conclude that the approaches relevant in a given setting depend on the purpose of the risk analysis, and that further research is required to make the possibilistic approaches operational in a risk analysis context.     

Complexity,simplicity, simplexity

“In the midst of order, there is chaos; but in the midst of chaos, there is order”, John Gribbin wrote in his book Deep Simplicity (p. 76). In this dialectical spirit, we discuss the generative tension between complexity and simplicity in the theory and practice of management and organization. Complexity theory suggests that the relationship between complex environments and complex organizations advanced by the well-known Ashby’s law, may be reconsidered: only simple organization provides enough space for individual agency to match environmental turbulence in the form of complex organizational responses. We suggest that complex organizing may be paradoxically facilitated by a simple infrastructure, and that the theory of organizations may be viewed as resulting from the dialectical interplay between simplicity and complexity.